MD Downloads: wrap some <paper-buttons>s in <template is="dom-if">

chrome/browser/resources/md_downloads/focus_row.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('downloads', function() {
   /**
    * @param {!Element} root
    * @param {?Node} boundary
    * @constructor
    * @extends {cr.ui.FocusRow}
    */
   function FocusRow(root, boundary) {
     cr.ui.FocusRow.call(this, root, boundary);
 
     this.addItem('name-file-link',
                  '#content.is-active:not(.show-progress) #name');
     assert(this.addItem('name-file-link', '#file-link'));
     assert(this.addItem('url', '#url'));
-    assert(this.addItem('show-retry', '#show'));
-    assert(this.addItem('show-retry', '#retry'));
-    assert(this.addItem('pause-resume', '#pause'));
-    assert(this.addItem('pause-resume', '#resume'));
-    assert(this.addItem('cancel', '#cancel'));
+    this.addItem('show-retry', '#show');
+    this.addItem('show-retry', '#retry');
+    this.addItem('pause-resume', '#pause');
+    this.addItem('pause-resume', '#resume');
+    this.addItem('cancel', '#cancel');
     this.addItem('controlled-by', '#controlled-by a');
     assert(this.addItem('danger-remove-discard', '#discard'));
     assert(this.addItem('restore-save', '#save'));
     assert(this.addItem('danger-remove-discard', '#danger-remove'));
     assert(this.addItem('restore-save', '#restore'));
     assert(this.addItem('remove', '#remove'));
   }
 
   FocusRow.prototype = {__proto__: cr.ui.FocusRow.prototype};
 
   return {FocusRow: FocusRow};
 });